A. Field of the Invention
The present invention involves a novel chewing gum formulation and a method of making the same. The chewing gum formulation is used to form a final chewing gum composition which contains an active ingredient which is released from the chewing gum as the gum is masticated in the mouth of the user. The chewing gum made from the chewing gum composition of the present invention is initially a compressed body, such as a tablet, which, in certain embodiments of the present invention, quickly dissociates into a multiplicity of small pieces upon initial chewing followed by a reformation of the pieces into a coherent mass of chewing gum after a few seconds of chewing. Both the chewing gum formulation and the chewing gum composition are in the form of a free-flowing particulate which is capable of being directly compressed at high speed by a standard tableting machine into chewing gum tablets.
B. Description of the Related Art
The prior art methods of producing compressible chewing gums involved one of the two techniques described below.
The first technique was to freeze the gum base or mixtures containing the gum base and then grind or otherwise comminute the frozen materials to obtain a particulate material containing the gum base. This particulate material could then be mixed with other materials (usually in particulate form) to create a compressible chewing gum. Some of the U.S. patents describing this technology are U.S. Pat. Nos. 2,290,120; 4,737,366; 5,711,961 and 5,866,179.
The second technique was to mix a dry powder (usually the sweetener) into a molten gum base while subjecting the mixture to shear (i.e., through the mixing force) and cooling. This technique causes the comminution of the mixture as the plasticity of the mixture decreases and the mixture becomes more rigid due to the effects of cooling and the addition of the dry particulate material. The primary U.S. patent describing this technique is U.S. Pat. No. 3,262,784, which is discussed in more detail below.
U.S. Pat. No. 3,262,784 describes a compressible chewing gum product and a method of producing the same. The compressible chewing gum product is a free-flowing particulate at room temperature which can be shaped by simple compression or blended with other finely-divided materials or with liquid materials. The chewing gum is formed by heating a chewing gum base until it is molten and then slowly mixing into the molten gum base dry, finely-divided sugar without adding any additional heat to the molten mass during the mixing step, until the sugar is completely dispersed in the chewing gum base. By the time all of the sugar has been mixed into the chewing gum base, the product is in the form of a non-tacky, friable mass, which due to the mixing operation, exists as chunks, lumps, granules and particles of widely varying size.
It is disclosed in this patent that the gum base must be molten when the sugar is first mixed with the gum base and that the chewing gum base cannot be added to the sugar (i.e., the order of addition of the components is essential). Further, the product that is obtained from the mixer, although non-tacky and friable, has a widely varying particle size.
Additional variations on the above-described prior art processes can be found in the patents discussed below.
U.S. Pat. No. 4,161,544 describes a process for making a pourable material for chewing gum that is supposed to be an improvement over the process described in U.S. Pat. No. 3,262,784. The process of this patent involves heating a dry base material to 60° to 120° C. and adding thereto dry sugar materials; polysaccharides; natural gums and swelling agents, mixing the ingredients at 60° to 120° C. for about 1–15 minutes, thereafter cooling the mixture to about 30° to minus 5° C. and continuing the mixing operation for another 1–15 minutes. This process is described as providing a pourable powder which can be compressed to desired shapes after being passed through a screen having a mesh size of about 1 mm.
U.S. Pat. No. 4,753,805 describes a process of producing a chewing gum tablet having a water content of about 2 to about 8% which involves forming a chewing gum composition by standard techniques (i.e., by mixing the secondary ingredients into a melted blend of the gum base and the sweetener until a homogeneous blend is obtained and then cooling the molten mixture until solid) and then grinding the chewing gum composition in the presence of a grinding aid to comminute the chewing gum composition. The comminuted chewing gum composition is then mixed with a compression aid, which is usually composed of several ingredients that have different functions (e.g., lubricants, glidants, and anti-adherents) and the final mixture is tableted.